Method of retarding the deterioration of rubber



Patented Dec. 39, 1930 WILLIAM S. CALCOTT AND WILLIAM A. DOUGLASS, OFPENNS GROVE, NEW JERSEY,

ASSIG-NORS TO E. I. DU FRONT DE NEMOURS 8:, COMPANY, OF VTTLMINGTON,DELA- WARE, A CORPORATION OF DELAWARE METHOD OF BETARDING THEDETERIORATION OF; RUBBER No Drawing.

This invention relates to a method of treating rubber and the resultingrubber product and is more particularly concerned with a method oftreatment whereby a rub' ber product is obtained which is unusually Theprimary object of this invention, D 0 T therefore, is to provide amethod for retarding the deterioration of rubber by the use of a newclass of compounds, which not only may be easily and economicallyprepared from readily available materials,but which at the same time donot retard the cure.

With these obj ectsin View it has nowbeen discovered that the diaminoand substituted diaminddiaryl-ketones may be added to a rubber mixwithout materially affecting the rate of cure and that the resultingrubber product when vulcanized has much greater resistance todeterioration than rubber containing, no antioxidant.

The products contemplated have the following general formula:

wherein A and A represent amino groups or alkl substituted or dialkylsubstituted In order to disclose the invention in detail,thefollowingexample of an actual embodiment thereof is presented. It shouldbe understood, however, that this example a is furnished purely forpurposes of illustration and that it is not the intention that theinvention be limited to the particular reagents, proportions, or otherconditions therein specified.

Application filed September 9, 1929. Serial No. 391,504.

Example 1 p-p-tetm-methg Z-diam/ino- I dphenyZ-Zcetone composition; theproportions are given by weight:

18.15 18.15 2.75 2.75 .G 0.5625 0.5625 Antioxidant 0.0 1.0

type described may be employed instead of the particular compound, theuse of which is illustrated in the example. Among such compounds whichpossess similar anti-aging properties maybe mentioned for purposes offurther illustration the following:

(1) 2 2-diamino-diphenyl-ketone NE. NHL

1 (H) l g (2) 2 3'-diamino-diphenyl-ketone NH; NH, 7

"2 4:-diamino--diphenyl-ketone IUD O ketone tone (41-)3:3-diamino-diphenyl-ketone ll g -amino-4-diethyl-amino-dipl1enyllretoneTO 16 4:4'-meth lamino-2:2-methyl-di- (5) 3:4 -diammo-diphenyl-ketone pg y y IHZ 1 7 Q 7 3 CH3 1 O E NH i1/ OE n p ny (17-dimethylaminodiethylamino-di- V phenyl-ketone.

HZN o -Nn, 0 O r 0H3)zN O- +C N o2na (7)4:4"-inethyl-amino-diphenyl-ketone Y O H r v H 7 (l8) 4 :4dimethylamino-2 :Q 'dimethyI l 7 v H3C N N V diphenyl lretone CH3 H 7(ma I w (8)3-z 3sdiamino-4c;4: dimethyl-diphenyl-- (GHS)QNOOON(CHMketone t HaOO,O CH3 (19) 4: 1 dimethylamino-3: 3-dimethyl- 99 p 1 It I Vdiphenyl-ketone V s (3H3 (HaC)2N--CN(OH3)2 j 0H3 j ll HzNQ-EONH; Inaddition, compounds resulting from the reaction ofp-p-diamino-diphenyl-ketone and enzyl chloride, ethylene chlorhydrin, orethylene dichloride have similar anti-aging v r V I properties Whencompounded in rubber. a c Moreover, it is obvious from the formulas z )z7 given hereinabove that the invention contem- 0 plates compounds inwhich the'aryl groups 2 dimethyl p y contain substituents such as alkyland alkoxy (.10) i amino 4' dimethyl amino diphenyl-ketone.

substituents and that such substituents do not tone materially alter'the value of the particular morn more I compounds as deteriorationinhibitors. Fur- O ther, it is obvious that corresponding dinaphg thyland phenyl-naphthyl compoundsmay be employed and exhibit similarproperties. (12) 3:3 dimethyl amino-diphenyl-lre However, of the manycompounds which tone fall Within the general class described here- NwflmMam), in by reason of their unusual eilect-iveness and their economy ofpreparation, the tetra- 60- methyl-diamino-diaryl-ketones are preferred.

Of this preferred class p-p-tetra-methyl-cliamino-diphenyl-ketonerepresents the pre- (13) 3 4' dnnethyl amino-diphenyl-kef d b di t 1 Theantioxidants describedabove may be I incorporated into the rubber by anywell r" 'known means, such as by milling them into O thevstoclr upontherolls of an ordinary mill. 0 Moreover, they can be employedin various(14) 4: 1 -inethy;lamino.- 3 :3 -methy l-dibe compounds d rubber it h Lkt such as, forexample, gutta percha, balata, 11 and synthetic rubber,and it istherefore to CH3 be understoodthat the invention'is notlim- NpHm ited toany particular rubber stock fmblj' compound. 120

oxidant in a solvent, or by employing it in vapor form. I 7

As many apparent and widely different embodiments of this invention maybe made without departing from the spirit thereof, it is to beunderstood that we do not limit ourselves'to the foregoing examples ordescription except as indicated in the following claims.

We claim:

1. The process of increasing the resistance of rubber to deteriorationwhich comprises incorporating with the rubber a compound having thefollowing general formula wherein each of A and A represents an aminogroup or a monoor dialkyl amino group, and R and R represent arylnuclei.

2. Ihe process of increasing the resistance of rubber to deteriorationwhich comprises incorporating with the rubberp-p-tetramethyl-diamino-diphenyl-ketone. V

3. In the art of vulcanizing rubber, the step of mixing with theunvulcanized rubber a vulcanizing agent and a compound having thegeneral formula II ARCRA wherein each of A and A represents an aminogroup or a monoor dialkyl amino group, and R and R represent arylnuclei, and thereafter vulcanizing.

l. In the art of vulcanizing rubber, the step of mixing with theunvulcanized rubber a vulcanizin'g agent and a compound of the type setforth in claim 1, in which formula at least one of A and A represents anallryl substituted amino group, and thereafter vulcanizing.

' 5. In the art of vulcanizing rubber, the step of mixing with theunvulcanized rubber a vulcanizing agent and a compound of the type setforth in claim 1, in which formula at least one of A and A represents adialkyl substituted amino group, and thereafter vulcaniz- 6. In the artof vulcanizlng rubber, the step of mixing with the unvulcanized rubber avulcanizing agent and a compound of the type set forth in claim 1, inwhich formula both A and A represent an alkyl substituted amino group,and thereafter vulcanizing.

7. In the art of vulcanizing rubber, the step of mixing 'withtheunvulcanized rubber a vulcanizing agent and'acompound of the type setforth in claim 1, inwhich formula bothA and A represent a dialkylsubstituted amino group, and thereaftervulcanizing.

8. In the art of vulcanizing rubber, the step of mixing with theunvulcanized rubber a vulcanizing agent and a compound of the type r setforth in claim 1, in which formula both R and R represent phenylradicals, and thereafter vulcanizing.

9. In the art of vulcanizing rubber, the step of mixing with theunvulcanized rubber a vulcanizing agent and a compound of the type setforthin claim 1, in which formula both A- and A represent an alkylsubstituted amino group, and both R and R represent phenyl nuclei, andthereafter vulcanizing.

, 10. Inthe art of vulcanizing rubber, the step of mixing with theunvulcanized rubber a vulcanizing agentandp-p'-tetra-methyldiamino-diphenyl-ketone, and thereafter vul canizing.

11. Rubber having incorporated therewith an anti-aging compound havingthe general formula wherein each of A and A represents an amino group ora monoor dialkyl amino group, and R and'R represent aryl nuclei.

12. Rubber having incorporated therewith p-p-tetra-methyl diaminodiphenyl-ketone, and thereafter vulcanizing.

13. Vulcanized rubber obtained by inc0r-' porating'with the rubber priorto vulcanization a vulcanizing agent and an anti-aging compound havingthe general formula a vulcanizing agent and1-4-methyl-aminodiphenyl-ketone. i v

17. Vulcanized rubber obtainable by incorporating with the rubber priorto vulcanization a vulcanizing agent and from 1 to 5% ofA-Q-diamino-diphenyl-ketone.

18(VulcaniZedrubberobtainable by incorporating with the rubber prior tovulcanization a Vulcanizing agent and from 1 to 5% 0f 4-4-methy1amin0-dipheny1-ketone.

In testimony whereof We afiixour signatures.

WILLIAM s. CALGOTT. WILLIAM A. DOUGLASS.

